Add hipMallocManaged default functional support (#1036)

* Add hipMallocManaged default functional support

* Fix build error

* Add dtest

tests/src/runtimeApi/memory/hipMallocManaged.cpp

@@ -0,0 +1,52 @@
+#include <hip/hip_runtime.h>
+#include <math.h>
+#include "test_common.h"
+
+/* HIT_START
+ * BUILD: %t %s ../../test_common.cpp
+ * RUN: %t -N 256M
+ * HIT_END
+ */
+
+__global__
+void add(int n, float *x, float *y)
+{
+    int index = blockIdx.x * blockDim.x + threadIdx.x;
+    int stride = blockDim.x * gridDim.x;
+    for (int i = index; i < n; i += stride)
+        y[i] = x[i] + y[i];
+}
+
+int main(int argc, char *argv[])
+{
+    HipTest::parseStandardArguments(argc, argv, true);
+    int numElements = N;
+    bool testResult = true;
+    float *A, *B;
+
+    hipMallocManaged(&A, numElements*sizeof(float));
+    hipMallocManaged(&B, numElements*sizeof(float));
+
+    for (int i = 0; i < numElements; i++) {
+        A[i] = 1.0f;
+        B[i] = 2.0f;
+    }
+
+    int blockSize = 256;
+    int numBlocks = (numElements + blockSize - 1) / blockSize;
+    dim3 dimGrid(numBlocks, 1, 1);
+    dim3 dimBlock(blockSize, 1, 1);
+    hipLaunchKernelGGL(add, dimGrid, dimBlock, 0, 0, numElements, A, B);
+
+    hipDeviceSynchronize();
+
+    float maxError = 0.0f;
+    for (int i = 0; i < numElements; i++)
+        maxError = fmax(maxError, fabs(B[i]-3.0f));
+
+    hipFree(A);
+    hipFree(B);
+    if(maxError == 0.0f)
+        passed();
+    failed("Output Mismatch\n");
+}